Seasonal change in growth rate, carrageenan yield and quality from the red alga (Kappaphycus striatus) cultivated in Cam Ranh bay

The red alga Kappaphycus striatus was cultivated at Camranh Bay, KhanhHoa, Vietnam. For a 30 day cultivation period, the alga showed the higher growth rate (4.1 - 5.8 % day-1) from October 2014 to April 2015 and in September 2015, while the lower growth rate (2.5 - 3.1 % day-1) was found from May to August 2015. The carrageenan quality was done for a 60-day cultivation period, the carrageenan yield and gel strength showed little variation with the higher values (28.1 - 28.7 % and 855 - 935 g cm-2, respectively) obtained from November 2014 to March 2015 and lower ones (25.1 - 26.7 % and 555 - 758 g cm-2, respectively) from April to September 2015. The data on moisture content of alga (33.5 - 36.8 %), clean anhydrous algal/salt ratio (0.92 - 1.07), and carrageenan yield obtained in this study fulfilled those of standards for carrageenophytes. This study shows that the red alga K. striatus can be grown in the tropical waters of the Camranh Bay during the northeast monsoon and a part of the southwest monsoon as a source of materials for carrageenan production.

PERFORMA RUMPUT LAUT Kappaphycus alvarezii HASIL SELEKSI DI PERAIRAN LAIKANG KABUPATEN TAKALAR

Peremajaan bibit melalui seleksi dapat dilakukan untuk perbaikan kualitas bibit rumput laut. Penelitian ini bertujuan untuk menentukan performa bibit rumput laut K. alvarezii hasil seleksi varietas Takalar, SIRICA, dan Bali. Desain penelitian adalah rancangan acak lengkap (RAL), dengan empat siklus pemeliharaan sebagai ulangan. Seleksi bibit dilakukan pada ketiga varietas dengan bibit non-seleksi sebagai kontrol internal. Pemeliharaan dilakukan di perairan Laikang, Takalar, Sulawesi Selatan selama empat siklus dengan durasi 30 hari/siklus. Pengukuran laju pertumbuhan harian (LPH), kandungan karagenan, kekuatan gel, dan monitoring kualitas air dilakukan setiap 30 hari. Data yang diperoleh dianalisis menggunakan analisis ragam (ANOVA). Hasil penelitian menunjukkan bahwa seleksi bibit berpengaruh signifikan terhadap LPH rumput laut (P<0,05). Rumput laut hasil seleksi memiliki LPH lebih tinggi, yakni: Bali (4,75 ± 0,04%/hari), SIRICA (4,74 ± 0,06%/hari), dan Takalar (4,62 ± 0,12%/hari) dibandingkan dengan kontrol internal Bali (3,94 ± 0,15%/hari), SIRICA (3,74 ± 0,10%/hari), dan Takalar (3,66 ± 0,32%/hari). Rumput laut hasil seleksi varietas Bali dan SIRICA memiliki kandungan karagenan yang relatif sama yakni (37,27 ± 6,68%) dan (37,08 ± 7,17%). Varietas Takalar memiliki kandungan karagenan yang rendah (31,84 ± 5,32%) namun memiliki kekuatan gel yang paling tinggi (570,03 ± 145,72 g/cm²) dibandingkan varietas Bali (444,39 ± 157,44 g/cm²) dan SIRICA (438,48 ± 72,70 g/cm²).Regeneration by selection method can improve the quality of seaweed seed. This study was aimed to determine the performance of selected seaweed seeds of K. alvarezii from Takalar, SIRICA, and Bali varieties. The experiments were arranged in a completely randomized design with four cycles cultivations as replications. In each variety, a batch of non-selected/regular seeds was cultivated serving as internal control. The seaweed was cultivated in Laikang waters, Takalar Regency, South Sulawesi for 30 days for each cycle. The measurements of daily growth rate (DGR), carrageenan yield, gel strength, and water quality were conducted every 30 days. The collected data were statistically analyzed using ANOVA. The results showed that the selected seeds showed faster growth than that of its respective control (P<0.05). The selected seed of three varieties of K. alvarezii had higher DGR: Bali (4.75 ± 0.04%/day), SIRICA (4.74 ± 0.06%/day), and Takalar (4.62 ± 0.12%/day) than that of control varieties, Bali (3.94 ± 0.15%/day), SIRICA (3.74 ± 0.10%/day), and Takalar (3.66 ± 0.32%/day). The selected seeds of Bali and SIRICA had similar carrageenan content (37.27 ± 6.68%) and (37.08 ± 7.17%), respectively. Takalar had the lowest carrageenan yield (31.84 ± 5.32) but had the highest gel strength (570.03 ± 145.72 g/cm²) compared to Bali (444.39 ± 157.44 g/cm²) and SIRICA (438.48 ± 72.70 g/cm²).

Epiphyte Identification on Kappaphycus alvarezii Seaweed Farming Area in Arungkeke Waters, Jeneponto and The Effect on Carrageenan Quality

Kappaphycus alvarezii which is widely cultivated at sea is susceptible to other algae that drift away and attach as epiphyte. This study aims to identify epiphyte on seaweed farming K. alvarezii and its effect on carrageenan quality. The study was conducted on K. alvarezii seaweed farming area in Jeneponto, South Sulawesi. Sample of epiphyte was obtained from four stations. Epiphyte was identified in laboratory based on its morphological characteristics and calculated its density. Carrageenan yield and gel strength of healthy seaweed and those infected one were analyzed in laboratory in triplicates for each sample. Data were statistically analyzed using independent samples t-test analysis. Present study showed that there were 6 epiphytes species on the seaweed farming area, namely: Entheromorpha intestinalis, Ceramium sp., Neosiphonia apiculata, Chaetomorpha crassa, Hypnea sp., and Gracilaria sp. The average of epiphytic density in cultivation area was (24.26±9.64)%. Healthy seaweed and infected one had significantly different carrageenan yield and gel strength (P<0.05). Healthy seaweed had higher carrageenan yield (48.17±1.62)% and gel strength (1130.76±8.42) g cm-² than infected seaweed which had carrageenan yield (42.47±0.23)% and gel strength (958.22±10.85) g cm-².